In TypeScript, You can iterate over iterable objects (including array
, map
, set
, string
, arguments object
and so on) using for...of
loop. To be an iterable, an object must implement the @@iterator
method.
Loop over Array
Example of using 'for...of'
to iterate over array
elements.
let myArray = [10, 20, 30]; for (let value of myArray) { console.log(value); //10 20 30 }
Loop over Map
Example of using 'for...of'
to iterate over map
entries.
let map = new Map(); map.set("A",1); map.set("B",2); map.set("C",3); //Iterate over map keys for (let key of map.keys()) { console.log(key); //A B C } //Iterate over map values for (let value of map.values()) { console.log(value); //1 2 3 } //Iterate over map entries for (let entry of map.entries()) { console.log(entry[0], entry[1]); //"A" 1 "B" 2 "C" 3 } //Using object destructuring for (let [key, value] of map) { console.log(key, value); //"A" 1 "B" 2 "C" 3 }
Loop over Set
Example of using 'for...of'
to iterate over set
entries.
let mySet = new Set(); mySet.add('A'); mySet.add('B'); mySet.add('C'); //Iterate over set for (let entry of mySet) { console.log(entry); //A B C }
Loop over String
Example of using 'for...of'
to iterate over string
. During iteration, you will get one single character from string
in each loop cycle.
let blogName:string = "howtodoinjava.com"; //Iterate over set for (let character of blogName) { console.log(character); //howtodoinjava.com }
Drop me your questions in comments section.
Happy Learning !!
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Jinisha
Hi Lokesh
Great site. Thanks for making this. I have a suggestion. I see let being used in lot of places. Suggest you to use const instead.